1. Field of the Invention
The present invention relates to a method for manufacturing a liquid discharge head.
2. Description of the Related Art
As a method for manufacturing an ink jet recording head applied in an ink jet recording method (liquid jet recording method), which is a typical example of a liquid discharge head, U.S. Pat. No. 6,555,480 describes a method of forming ink supply ports that penetrate through a silicon substrate by reactive ion etching (RIE).
Moreover, US Patent Publication No. 2009/0065472 describes a method of using a layer of aluminum, which is metal, as an etch-stop layer at the time of forming supply ports on a silicon substrate by reactive ion etching and defining an opening shape in the aluminum layer. According to this method, it is considered that it enables the suppression of the occurrence of notching when silicon is etched by reactive ion etching.
However, when metals such as aluminum used for the stop layer are diffused into the silicon substrate, a void may be generated in the stop layer, and accordingly, etching resistance will be lost. Moreover, there is a concern that the RIE for forming the supply ports would not progress smoothly due to the aluminum diffused into the silicon substrate. As the reason for this, it is supposed to be because, although, for example, it is common to use fluorine gas such as SF6 to perform reactive ion etching of silicon, aluminum will not etch with fluorine gas but will remain as aluminum fluoride. Since aluminum dissolves in an etching solution for crystal anisotropic wet etching of silicon, such a problem was not conceived of when wet etching was employed.